A survey is given of the physical properties, composition and crystal structure of intermetallic compounds formed between rare-earth elements and 3d transition elements. Apart from binary compounds the results of pseudobinary series are also considered. The magnetic properties determined by the exchange interactions involving 4f as well as 3d electrons, are discussed together with experimental results available on magnetovolume effects and various resonance techniques such as NMR and the Mossbauer effect.

https://iopscience.iop.org/article/10.1088/0034-4885/40/10/002/pdf

Intermetallic compounds of rare-earth and 3d transition metals

The stresses that develop in thin films on substrates can be detrimental to the reliability of thin film electronic devices. In order to design these devices for improved mechanical reliability, an...

Stresses and deformation processes in thin films on substrates

The tetragonal L10 family of ferromagnets including the Co-Pt, Fe-Pt, Fe-Pd and Mn-Al alloy systems exhibits high, uniaxial magnetocrystalline anisotropies with first anisotropy constants K1 ~ 107–108 ergs/cm3. The domain parameters of these materials are similar to the rare earth permanent magnets and the defect structure is dominated by planar faults such as APB's, stacking faults, and twins. In this study the micromagnetic analysis of Kronmuller has been applied to elucidate the mechanism of coercivity controlling the hysteresis of the polytwinned L10 FePd equiatomic alloy and the results are consistent with pinning control involving atomically thick, planar defects. Also, Lorentz microscopy has been used to observe the interaction of magnetic domain walls with the planar faults characteristic of these materials. Finally, a thermomechanical treatment involving concomitant ordering and recrystallization is shown to eliminate the well-known polytwinned structures which generally evolve during the formation of the L10 phase leading to enhanced coercivities. The fundamental structure-property relationships involved are discussed.

Magnetic hardening and coercivity mechanisms in L10 ordered FePd ferromagnets

Substrate curvature and submicron indentation measurements have been used recently to study plastic deformation in thin films on substrates. In the present work both of these techniques have been employed to study the strength of aluminum and tungsten thin films on silicon substrates. In the case of aluminum films on silicon substrates, the film strength is found to increase with decreasing thickness. Grain size variations with film thickness do not account for the variations in strength. Wafer curvature measurements give strengths higher than those predicted from hardness measurements suggesting the substrate plays a role in strengthening the film. The observed strengthening effect with decreased thickness may be due to image forces on dislocations in the film due to the elastically stiffer silicon substrate. For sputtered tungsten films, where the substrate is less stiff than the film, the film strength decreases with decreasing film thickness.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/EB977481F905993208EB4B407754569A/S0884291400014734a.pdf/div-class-title-plastic-properties-of-thin-films-on-substrates-as-measured-by-submicron-indentation-hardness-and-substrate-curvature-techniques-div.pdf

Plastic properties of thin films on substrates as measured by submicron indentation hardness and substrate curvature techniques

https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=1222&context=ameslab_manuscripts

Current progress and future challenges in rare-earth-free permanent magnets

The critical field strength at which a classical domain wall moves through a perfect ferromagnetic crystal of simplified structure is calculated as a function of the ratio between anisotropy energy K and ferromagnetic coupling energy C , taking into account the discrete nature of the spins. When K approaches C intrinsic wall pinning becomes appreciable with critical fields approaching the anisotropy field when K \gg C . For K/C \geq 2/3 , the wall has a thickness of one atomic distance and thus resembles a ferroelectric wall.

Calculation of intrinsic coercivity of magnetic domain walls in perfect crystals

Phase transformations in pure and carbon-doped Al45Mn55 alloys

Metal film precision resistors: Resistive metal films and a new resistor concept

On a series of Ag‐Al, Ag‐Au, Ag‐Cu, Au‐Cu, and Au‐Fe thin films, made by vapor deposition, both ultramicrohardness and internal stress were determined as a function of the chemical composition of the deposits. In order to interpret these results microstructural investigations were performed using x‐ray diffraction and transmission electron microscopy, supplemented by electrical resistivity measurements. The observed data on hardness and internal stress can be well understood with the help of the metastable phase diagram of the alloy films. In the case of single‐phase solid solutions, internal stresses are tensile. Compound formation, phase decomposition, or ordering are accompanied with dramatic changes of the internal stresses. With indentation experiments at very low loads the hardness‐concentration dependences were observed in the case of films having a thickness of 1 μm only. Metallic films in general are characterized by a very high defect concentration. Moreover, a dramatic reduction of the average grain size was observed upon alloying. The resulting hardness increase may be understood in terms of a mechanism implying the blocking of the motions of dislocations.

J.J. Van Den Broek

Papers

Calculation of intrinsic coercivity of magnetic domain walls in perfect crystals

Phase transformations in pure and carbon-doped Al45Mn55 alloys

Metal film precision resistors: Resistive metal films and a new resistor concept

Mechanical properties of thin alloy films: Ultramicrohardness and internal stress

Permanent magnetism and microstructure in τ-AlMn(C)